Wind power
Windmills have been used for pumping water or grinding grain for centuries. The windmill's modern equivalent – a wind turbine – uses wind energy to generate electricity. Pros

Safe

Inexhaustible

Free

Cons

Wind speed is variable and unreliable

Wind farms are typically located in high, exposed, rural locations, where they can be seen as eyesores

Often noisy, although modern turbines are quieter than their predecessors

Wildlife habitats can be disrupted and there is a risk of birds getting caught in the blades

Off-shore wind farms go some way to solving these problems, but they are expensive to build and maintain. It is cheaper to put more coal into an existing power station than to build a new wind farm.

How it works
Most wind turbines look similar to ships' propellers. Wind turns the turbine’s blades, gears increase the rotational speeds. The rotating turbine shaft drives the generator which transforms the mechanical energy to electrical energy.

Manufacturers are now producing giant turbines – 90 metres tall, with rotor diameters bigger than the wingspan of a jumbo jet. One standard-issue turbine can produce at least 1 megawatt of electricity, enough to supply at least 800 houses.

The world market for wind turbines has been growing by an average of 40% a year since 1995. But wind farms still only produce a tiny fraction of the world’s energy. There are currently about 60 operating wind farms in the UK, supplying enough power for 250,000 homes each year, or about 0.3% of total UK electricity consumption.